Use of pentagonally supported palladium catalyst in the preparation of tertiary butyl alcohol from tertiary butyl hydroperoxide

ABSTRACT

A method for preparing tertiary butyl alcohol wherein a feedstock comprising a solvent solution of tertiary butyl hydroperoxide in tertiary butyl alcohol or a mixture of tertiary butyl alcohol with isobutane is charged to a hydroperoxide decomposition reaction zone containing a catalytically effective amount of a hydroperoxide decomposition catalyst consisting essentially of pentagonally cross-sectioned alumina having palladium deposited thereon and is brought into contact with the catalyst in liquid phase with agitation under hydroperoxide decomposition reaction conditions to convert the tertiary butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the catalytic decomposition of tertiary butylhydroperoxide (TBHP). More particularly, this invention relates to amethod for the preparation of tertiary butyl alcohol (TBA) by thecatalytic decomposition of tertiary butyl hydroperoxide. Still moreparticularly, this invention relates to a method wherein apentagonally-shaped alumina support coated with palladium is used tocatalyze the substantially selective decomposition of tertiary butylhydroperoxide to tertiary butyl alcohol.

2. Prior Art

It is known to react isobutane with oxygen, either thermally orcatalytically, to form a peroxidation reaction product wherein theprincipal peroxide that is formed is tertiary butyl hydroperoxide. It isalso known to thermally or catalytically decompose the tertiary butylhydroperoxide to form tertiary butyl alcohol.

In the text entitled "Organic Peroxides" edited by Daniel Swern (WileyInterscience, a Division of John Wiley & Sons, New York), in Vol. II onpage 157 it is stated that the metal-ion-catalyzed decomposition ofprimary hydroperoxides yields mainly alcohols, aldehydes and carboxylicacids, citing as an example the decomposition of hydroxymethylhydroperoxide with aqueous ferrous sulfate to provide formaldehyde,formic acid and water.

Quin U.S. Pat. No. 2,854,487 discloses the hydrogenation of hydrocarbonperoxides in the presence of hydrogen and palladium on activated aluminato provide carbinols.

In Massie U.S. Pat. No. 3,775,472 a process is disclosed wherein alkylsubstituted aromatic hydrocarbons are oxidized to products such asaromatic alcohols, aldehydes and carboxylic acids in the presence ofruthenium compounds.

Grane U.S. Pat. No. 3,474,151 discloses that tertiary butyl alcoholstarts to dehydrate at 450° F. and to decompose at a "rapid rate" attemperatures above 475° F. Grane discovered, however, that residualquantities of hydroperoxide contaminants present in tertiary butylalcohol could be thermally decomposed by heating the contaminatedtertiary butyl alcohol at a temperature of 375° to 475° F. for about 1to 10 minutes.

Grane et al. U.S. Pat. No. 4,294,999 discloses a process whereinisobutane is oxidized in a pressured reactor in the presence of asolubilized molybdenum catalyst to provide a mixture of tertiary butylalcohol, tertiary butyl hydroperoxide, methanol, acetone, and otheroxygen-containing compounds. The tertiary butyl hydroperoxide isthermally decomposed under pressure at about 280° F. to provide atertiary butyl alcohol product containing only residual quantities oftertiary butyl hydroperoxide which are then decomposed in accordancewith Grane U.S. Pat. No. 3,474,151 by heating the tertiary butyl alcoholat 375° to 475° for about 1 to 10 minutes. Heating tertiary butylalcohol containing small amounts of peroxides at high temperatures foreven short periods of time to remove the peroxides produces undesirableproducts such as isobutylene.

Grane et al. U.S. Pat. No. 4,296,262 discloses a related process whereinisobutane is reacted with oxygen in a reaction zone for a residence timeof about 1 to 10 hours at a temperature of about 240° to about 340° F.and a pressure of about 100 to about 1000 psig. in the presence of acatalytically effective amount of a soluble molybdenum catalyst. Aliquid stream comprising tertiary butyl alcohol is recovered from thereaction mixture and fed to a decomposition zone wherein the tertiarybutyl hydroperoxide contained therein is decomposed by "hot aging" at250°-350° F. at a pressure lower than the pressure in the oxidationzone. The tertiary butyl alcohol can be further subjected to a clean-uptreatment at 375°-475° F. for 1 to 10 minutes. Worrell et al. in U.S.Pat. No. 4,296,263 disclose a related process wherein the feedstock is amixture of normal butane with isobutane and wherein the oxidationcatalyst is a soluble form of chromium, cobalt, nickel, manganese,molybdenum, or a mixture thereof.

In U.S. Pat. No. 3,505,360, Allison et al. disclose a method wherein analkenyl hydroperoxide is decomposed in the presence of a catalyst basedon a compound of a Group IV-A, V-A or VI-A metal. Taylor et al., in U.S.Pat. No. 4,508,923 disclose the use of a catalyst system comprisingruthenium and chromium for decomposing organic hydroperoxides. The useof a cobalt borate catalyst for the decomposition of hydroperoxides isdisclosed in Sanderson et al. U.S. Pat. No. 4,547,598.

Taylor et al. U.S. Pat. No. 4,551,553 is directed to a process for theformation of alcohols such as tertiary butyl alcohol by the catalyticdecomposition of an organic hydroperoxide such as tertiary butylhydroperoxide using a binary catalyst composed of a mixture of aruthenium compound with a chromium compound. It is stated that the useof the binary catalyst eliminates the need for stabilizing ligands.

Sanderson et al. disclose the use of a variety of catalysts for thedecomposition of tertiary butyl hydroperoxide in a series of U.S.patents, including a catalyst composed of unsupported nickel, copper,chromia and iron (U.S. Pat. No. 4,704,482), a catalyst composed of iron,copper, chromia and cobalt (U.S. Pat. No. 4,705,903), a catalystcomposed of a base treated hydrogenation catalyst from groups VIB orVIIIB of the Periodic Table (U.S. Pat. No. 4,742,179), a catalystconsisting essentially of nickel, copper, chromium and barium (U.S. Pat.No. 4,873,380), a catalyst composed of a metal phthalocyanine promotedwith a rhenium compound (U.S. Pat. No. 4,910,349), a catalyst composedof a base promoted metal phthalocyanine compound (U.S. Pat. No.4,912,269), a catalyst composed of a soluble ruthenium compound promotedwith a bidentate ligand (U.S. Pat. No. 4,912,033), a catalyst composedof a metal porphine such as iron (III) or manganese (III) promoted withan alkyl thiol or an amine, a catalyst composed of an imidazole promotedmetal phthalocyanine compound (U.S. Pat. No. 4,912,266), (U.S. Pat. No.4,922,034), a catalyst composed of a metal phthalocyanine promoted witha thiol and a free radical inhibitor (U.S. Pat. No. 4,922,035), acatalyst composed of a borate promoted metal phthalocyanine (U.S. Pat.No. 4,922,036), or a catalyst composed of a soluble ruthenium compoundand an iron compound such as an acetate, a borate, a bromide, achloride, a 1,3-propanedionate, a 2-ethyl-hexanoate, an iodide, anitrate, a 2,4-pentanedionate, a perchlorate or a sulfate (U.S. Pat. No.5,025,113).

BACKGROUND INFORMATION

When isobutane is reacted with molecular oxygen, the principal productsof the reaction are tertiary butyl alcohol and tertiary butylhydroperoxide. However, minor amounts of other contaminants are alsoformed.

In addition, a minor amount of water will be formed, which will normallyamount to about 0.5 to 1 wt. % of the reactor effluent. The amount ofbyproduct water that is produced is a function of the severity of thereaction conditions employed and will tend to increase as the severityof the reaction conditions is increased.

As indicated, tertiary butyl hydroperoxide is useful as a raw materialfor the manufacture of tertiary butyl alcohol. The tertiary butylalcohol can be formed by catalytic decomposition of the tertiary butylhydroperoxide. In the Williams et al. process disclosed in U.S. Pat. No.3,472,876, an oxygen-containing gas was charged to a reactor containingisobutane and an oxidation catalyst to provide a reaction mixturecomprising tertiary butyl alcohol, tertiary butyl hydroperoxide,acetone, and tertiary butyl ether. The reported results in the patentindicate that there was a comparatively low rate of conversion and acomparatively poor selectivity of the reaction to tertiary butylalcohol.

SUMMARY OF THE INVENTION

In accordance with the present invention, a solvent solution of atertiary butyl hydroperoxide charge stock is brought into contact with acatalytically effective amount of a hydroperoxide decomposition catalystin a hydroperoxide decomposition reaction zone in liquid phase withagitation to convert the tertiary butyl hydroperoxide to decompositionproducts, principally tertiary butyl alcohol, the hydroperoxidedecomposition catalyst being a supported hydroperoxide decompositioncatalyst consisting essentially of pentagonally cross-sectioned pelletsof alumina having deposited thereon from about 0.1 to about 1 wt. % of amixture of palladium and tertiary butyl alcohol is recovered from theproducts of the hydroperoxide decomposition reaction.

The tertiary butyl alcohol will not be the only decomposition productthat is formed. Minor amounts of other oxygen-containing materials suchas those listed above will also be formed.

The tertiary butyl alcohol that is recovered from the decompositionreaction mixture will be contaminated with the oxygenated impurities.

DESCRIPTION OF THE PROCESS OF THE PRESENT INVENTION

The starting materials for the process of the present invention are atertiary butyl hydroperoxide feedstock and a supported palladium of starshaped alumina.

The Tertiary Butyl Hydroperoxide Feedstock

The tertiary butyl hydroperoxide charge stock may comprise an isobutaneoxidation product wherein the tertiary butyl hydroperoxide is dissolvedin a mixture of isobutane and tertiary butyl alcohol or may comprise anisobutane oxidation product enriched by the addition of tertiary butylalcohol, such that the solution of tertiary butyl alcohol in the mixtureof isobutane with tertiary butyl alcohol contains from about 5 to about30 wt. % of tertiary butyl hydroperoxide.

Alternately, the isobutane reaction product may be charged to adistillation zone where unreacted isobutane is removed as a distillatefraction for recycle to thereby provide a solution of tertiary butylhydroperoxide in tertiary butyl alcohol containing about 5 to about 30wt. % of tertiary butyl hydroperoxide.

The Catalyst System

The hydroperoxide decomposition catalyst to be used in accordance withthe present invention is a supported hydroperoxide decompositioncatalyst consisting essentially of pentagonally cross-sectioned pelletsof alumina having deposited thereon from about 0.1 to about 5 wt. % ofpalladium and tertiary butyl alcohol is recovered from the products ofthe hydroperoxide decomposition reaction.

Catalytic Decomposition of Tertiary Butyl Hydroperoxide

The process of the present invention may be conducted continuously bypassing the reactants through a tubular reactor.

The catalytic decomposition of the tertiary butyl hydroperoxide ispreferably conducted at a temperature within the range of about 20° toabout 160° C. and, more preferably, at a temperature within the range ofabout 80° to about 100° C. The reaction is preferably conducted at apressure sufficient to keep the reactants and the reaction products inliquid phase. A pressure of about 0 to about 10,000 psig. may be used,if desired.

As described hereafter, the rates of the charge solution to the reactionzone should be adjusted in order to provide an appropriate contact timewithin the reactor.

In accordance with a preferred embodiment of the present invention,isobutane is reacted with oxygen in an oxidation zone under oxidationreaction conditions including a temperature of about 135° to about 155°C., a pressure of about 300 to about 800 psig., and a holding time ofabout 2 to about 6 hours to provide an initial oxidation reactionproduct comprising unreacted isobutane, tertiary butyl hydroperoxide,tertiary butyl alcohol, and oxygen-containing by-products. The initialoxidation reaction product is then used as the tertiary butylhydroperoxide charge stock of the present invention. If theconcentration of tertiary butyl hydroperoxide in the tertiary butylhydroperoxide charge stock is more than about 30 wt. % of the initialoxidation reaction product, the initial oxidation reaction product canbe diluted with an amount of tertiary butyl alcohol sufficient to lowerthe concentration of the tertiary butyl hydroperoxide to a desiredpercentage, to provide, for example, a tertiary butyl hydroperoxidecharge stock containing from about 15 to about 25 wt. % of tertiarybutyl hydroperoxide.

Alternately, the initial oxidation reaction product may be fractionatedin any appropriate manner (e.g., by distillation in a distillation zone)to remove the isobutane therefrom for recycle and to provide a solutionof tertiary butyl hydroperoxide and tertiary butyl alcohol which willnormally contain from about 5 to about 30 wt. % of tertiary butylhydroperoxide.

The solution of tertiary butyl hydroperoxide in tertiary butyl alcoholis then charged to a catalytic hydroperoxide decomposition zone where itis brought into contact with a catalyst of the present invention tosubstantially selectively convert the tertiary butyl hydroperoxide totertiary butyl alcohol with high yields and selectivities.

As indicated, the catalytic decomposition of the tertiary butylhydroperoxide in the catalytic hydroperoxide decomposition reaction zonemay suitably be conducted at a temperature within the range of about 20°to about 160° C., preferably from about 60° to about 120° C., and morepreferably from about 80° to 100° C. at autogenous pressure or ifdesired at a super-atmospheric pressure up to 10,000 psig.

The process of the present invention is practiced in a continuous mannerby continuously charging the tertiary butyl hydroperoxide charge stockto a reactor containing a fixed bed of pelleted hydroperoxidedecomposition catalyst, at a space velocity that is suitably in therange of about 0.5 to about 3 volumes of tertiary butyl hydroperoxidecharge stock per volume of catalyst per hour. Preferably, the spacevelocity is within the range of about 1 to about 3 volumes of tertiarybutyl hydroperoxide charge stock per volume of catalyst per hour.

The reaction product from the tertiary butyl hydroperoxide decompositionstep may then be fractionated in any suitable manner, such as bydistillation to recover the tertiary butyl alcohol.

SPECIFIC EXAMPLES

The invention will be further illustrated by the following specificexamples which are given by way of illustration and not as limitationson the scope of this invention.

Reactor

The reactor was a stainless steel tube (0.51"×29") which waselectrically heated. Liquid feed was pumped into the bottom of thereactor. 1 Pressure regulation was with a Skinner Uni-Flow valve and aFoxboro controller. The liquid feed was pumped with a Ruska dual drivepump.

Feed

20% TBHP was prepared from 55% isobutane peroxidation reactor effluentby diluting with commercial TBA.

Catalyst

A 200 cc sample of 1% palladium supported on a pentagonallycross-sectioned alumina pellets, where the palladium has been coatedonto the exterior surface of the alumina to an average thickness of 200microns. The average diameter of the pellets was 2 mm. The pellets wereplaced in a reactor and heated to 140° C. for 4.0 hours in a stream ofhydrogen. The sample was cooled under hydrogen and stored under anitrogen atmosphere.

Analytical

Analysis of the reactor effluent was by GC. Details are given in thefollowing tables.

                                      TABLE 1                                     __________________________________________________________________________    CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE                               TO TERT-BUTYLALCOHOL                                                          Notebook Number                                                                             6952-39-G                                                                           7012-02-1                                                                           7012-02-2                                                                           7012-02-3                                                                           7012-02-4                               __________________________________________________________________________    Catalyst            1% Pd on Al.sub.2 O.sub.3 pellets (pentagonal                                 cross-section)                                            Catalyst (cc)       100   100   100   100                                     Pressure (psig)     300   300   300   300                                     Feed Rate (cc/Hr.)  50    50    50    50                                      Temperature (°C.)                                                                          60    80    100   120                                     Time on Stream (Hr) 4     4     4     4                                       Space Vel. (cc/cc)  0.5   0.5   0.5   0.5                                     TBHP Conversion (mol. %)                                                                          75.8  97.4  100.0 100.0                                   Selectivity IC4═ (mol. %)                                                                     0.0   0.0   0.0   0.4                                     Sel. Acetone (mol. %)                                                                             6.4   14.3  21.3  23.1                                    Sel. Methanol (mol. %)                                                                            1.1   3.4   2.6   5.4                                     Sel. TBA (mol. %)   84.1  81.3  76.0  75.3                                    Sel. DTBP (mol. %)  9.5   4.5   2.7   1.6                                     Composition                                                                   IC4═      0.000 0.000 0.000 0.002 0.050                                   MEOH/MF       0.005 0.065 0.248 0.192 0.399                                   Acetone       0.013 0.650 1.852 2.834 3.067                                   TBA           78.494                                                                              91.456                                                                              95.420                                                                              95.254                                                                              95.261                                  DTBP          0.049 1.251 0.770 0.490 0.309                                   TBHP          20.512                                                                              4.969 0.539 0.002 0.003                                   __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE                               TO TERT-BUTYLALCOHOL                                                          Notebook Number                                                                             6952-39-G                                                                           7012-03-1                                                                           7012-03-2                                                                           7012-03-3                                                                           7012-03-4                               __________________________________________________________________________    Catalyst            1% Pd on Al.sub.2 O.sub.3 pellets (pentagonal                                 cross-section)                                            Catalyst (cc)       100   100   100   100                                     Pressure (psig)     300   300   300   300                                     Feed Rate (cc/Hr.)  100   100   100   100                                     Temperature (°C.)                                                                          60    80    100   120                                     Time on Stream (Hr) 4     4     4     4                                       Space Vel. (cc/cc)  1.0   1.0   1.0   1.0                                     TBHP Conversion (mol. %)                                                                          57.1  n.d.  84.7  100.0                                   Selectivity IC4═ (mol. %)                                                                     0.0   n.d.  0.0   0.4                                     Sel. Acetone (mol. %)                                                                             6.1   n.d.  11.3  24.4                                    Sel. Methanol (mol. %)                                                                            1.2   n.d.  3.1   4.1                                     Sel. TBA (mol. %)   84.6  n.d.  83.6  74.3                                    Sel. DTBP (mol. %)  9.3   n.d.  5.1   1.3                                     Composition                                                                   IC4═      0.000 0.000 0.000 0.000 0.051                                   MEOH/MF       0.005 0.057 0.000 0.198 0.305                                   Acetone       0.013 0.472 0.000 1.283 3.237                                   TBA           78.494                                                                              88.259                                                                              0.000 92.557                                                                              95.262                                  DTBP          0.049 0.936 0.000 0.765 0.269                                   TBHP          20.512                                                                              8.790 0.000 3.133 0.003                                   __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE                               TO TERT-BUTYLALCOHOL                                                          Notebook Number                                                                             6952-39-G                                                                           7012-04-1                                                                           7012-04-2                                                                           7012-04-3                                                                           7012-04-4                               __________________________________________________________________________    Catalyst            1% Pd on Al.sub.2 O.sub.3 pellets (pentagonal                                 cross-section)                                            Catalyst (cc)       100   100   100   100                                     Pressure (psig)     300   300   300   300                                     Feed Rate (cc/Hr.)  200   200   200   200                                     Temperature (°C.)                                                                          60    80    100   120                                     Time on Stream (Hr) 4     4     4     4                                       Space Vel. (cc/cc)  2.0   2.0   2.0   2.0                                     TBHP Conversion (mol. %)                                                                          34.2  71.0  93.9  100.0                                   Selectivity IC4═ (mol. %)                                                                     0.0   0.0   0.0   0.3                                     Sel. Acetone (mol. %)                                                                             5.8   9.9   16.1  25.1                                    Sel. Methanol (mol. %)                                                                            1.4   2.6   5.7   4.1                                     Sol. TBA (mol. %)   85.4  84.5  80.8  73.6                                    Sel. DTBP (mol. %)  8.8   5.6   3.2   1.3                                     Composition                                                                   IC4═      0.000 0.000 0.000 0.000 0.043                                   MEOH/MF       0.005 0.040 0.142 0.396 0.306                                   Acetone       0.013 0.273 0.944 2.009 3.327                                   TBA           78.494                                                                              84.360                                                                              90.336                                                                              93.977                                                                              95.231                                  DTBP          0.049 0.550 0.712 0.541 0.260                                   TBHP          20.512                                                                              13.505                                                                              5.947 1.246 0.010                                   __________________________________________________________________________

A novel commercial catalyst (1% palladium on star-shaped aluminasupport) was very active for the conversion of TBHP. Selectivity to TBAwas good. For example, at 80° C. and a space velocity of 0.5, thiscatalyst gave 97.4% TBHP conversion and a selectivity to TBA of 81.3%,acetone of 14.3%, methanol of 3.4% and DTBP of 4.5%.

"Typical" peroxide conversion catalysts under these conditions usuallygive 80% or less conversion.

Having thus described our invention, what is claimed is:
 1. In a methodwherein a solvent solution of a tertiary butyl hydroperoxide chargestock is brought into contact with a catalytically effective amount of ahydroperoxide decomposition catalyst in a hydroperoxide decompositionreaction zone in liquid phase with agitation to convert said tertiarybutyl hydroperoxide to decomposition products, principally tertiarybutyl alcohol, the improvement which comprises:a) using, as saidhydroperoxide decomposition catalyst, a supported hydroperoxidedecomposition catalyst consisting essentially of pentagonallycross-sectioned pellets of alumina having palladium deposited thereon,and b) recovering tertiary butyl alcohol from the products of saidhydroperoxide decomposition reaction.
 2. A method as in claim 1 whereinthe solvent comprises tertiary butyl alcohol.
 3. A method as in claim 1wherein the solvent comprises a mixture of isobutane with tertiary butylalcohol.
 4. In a method wherein a solution of a tertiary butylhydroperoxide charge stock in tertiary butyl alcohol that contains fromabout 5 to about 30 wt. % of tertiary butyl hydroperoxide is broughtinto contact with a catalytically effective amount of a hydroperoxidedecomposition catalyst in a hydroperoxide decomposition reaction zone inliquid phase with agitation under hydroperoxide conversion conditionsincluding a temperature within the range of about 25° to about 250° C.and a pressure of about 0 to about 1,000 psig to convert said tertiarybutyl hydroperoxide to decomposition products, principally tertiarybutyl alcohol, the improvement which comprises:a) using, as saidhydroperoxide decomposition catalyst, a supported hydroperoxidedecomposition catalyst consisting essentially of pentagonallycross-sectioned pellets of alumina having deposited thereon from about0.1 to about 1 wt. % of palladium, and b) recovering tertiary butylalcohol from the products of said hydroperoxide decomposition reaction.5. A method as in claim 4 wherein the temperature is in the range ofabout 40° to about 150° C. and the pressure is about 0 psig.
 6. In amethod wherein a solution of a tertiary butyl hydroperoxide charge stockin a mixture of isobutane with tertiary butyl alcohol that contains fromabout 5 to about 30 wt. % of tertiary butyl hydroperoxide is broughtinto contact with a catalytically effective amount of a hydroperoxidedecomposition catalyst in a hydroperoxide decomposition reaction zone inliquid phase under hydroperoxide conversion conditions including atemperature within the range of about 25° to about 250° C. and apressure of about 0 to about 10,000 psig to convert said tertiary butylhydroperoxide to decomposition products, principally tertiary butylalcohol, the improvement which comprises:a) using, as said hydroperoxidedecomposition catalyst, a diluted hydroperoxide decomposition catalystconsisting essentially of pentagonally cross-sectioned pellets ofalumina having deposited thereon from about 0.1 to about 1 wt. % ofpalladium and a diluent consisting essentially of about 100 to about 500wt. % of titania, based on the hydroperoxide decomposition catalyst, b)recovering tertiary butyl alcohol from the products of saidhydroperoxide decomposition reaction.
 7. A method as in claim 6 whereinthe temperature is in the range of about 40° to about 150° C. and thepressure is about 0 psig.